An optical switching element for use in an optical cross-bar array, includes a magnetically responsive curtain that switches between an extended state and a deflected state in response to an applied switching-field. The switching element includes a curtain that moves in response to a magnetic field. The curtain has a fixed edge attached to a substrate and a free edge opposite the fixed edge. A first magnetic-field source magnetically coupled to the curtain generates a first magnetic field that urges the curtain into an extended position in which the curtain intercepts the optical beam. A second magnetic-field source, also magnetically coupled to the curtain, generates a second magnetic field that urges the curtain into a deflected position in which the curtain avoids intercepting the optical beam.